Differential Rotation
The role of differential rotation appears to be crucial to the sunspot issue and of the active Sun in
general. If the Sun did not rotate differentially, the discussion of the left panel suggests that many
of the features that we associate with the active Sun might go away.
But we expect almost all stars to
rotate differentially since they are fluids; thus, this is another argument leading us to expect
other stars to exhibit periodic magnetic activity of the kind found for the Sun.